Among such types of bags, an air bag for use in restraining a vehicle occupant during collision has been typically made of woven fabric of fiber such as polyamide fiber with silicone rubber coating. As alternatives, an air bag made of heat-resisting resin sheet (JPA No. 2-31965) and an air bag made of elastomer (JPA No. 4-266544) were recently proposed.
Such heat-resisting resin sheets or elastomer sheets are cut out in desired sizes from a large sheet and then bonded together by adhesives or fusion.
The method of cutting out the sheets in desired sizes from the large sheet takes a lot of time, thereby lowering the productivity.
When the resin sheets are bonded together by adhesive or fusion, defective bonded portions may be formed because of bulkiness and irregularity of the sheets.